OgreShadowCaster.h

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/*
-----------------------------------------------------------------------------
This source file is part of OGRE
    (Object-oriented Graphics Rendering Engine)
For the latest info, see http://www.ogre3d.org/

Copyright (c) 2000-2012 Torus Knot Software Ltd

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
-----------------------------------------------------------------------------
*/
#ifndef __ShadowCaster_H__
#define __ShadowCaster_H__

#include "OgrePrerequisites.h"
#include "OgreRenderable.h"


namespace Ogre {


    class _OgreExport ShadowRenderable : public Renderable, public ShadowDataAlloc
    {
    protected:
        MaterialPtr mMaterial;
        RenderOperation mRenderOp;
        ShadowRenderable* mLightCap; // used only if isLightCapSeparate == true
    public:
        ShadowRenderable() : mMaterial(), mLightCap(0) {}
        virtual ~ShadowRenderable() { delete mLightCap; }
        void setMaterial(const MaterialPtr& mat) { mMaterial = mat; }
        const MaterialPtr& getMaterial(void) const { return mMaterial; }
        void getRenderOperation(RenderOperation& op) { op = mRenderOp; }
        RenderOperation* getRenderOperationForUpdate(void) {return &mRenderOp;}
        void getWorldTransforms(Matrix4* xform) const = 0;
        Real getSquaredViewDepth(const Camera*) const{ return 0; /* not used */}
        const LightList& getLights(void) const;
        bool isLightCapSeparate(void) const { return mLightCap != 0; }

        ShadowRenderable* getLightCapRenderable(void) { return mLightCap; }
        virtual bool isVisible(void) const { return true; }

        virtual void rebindIndexBuffer(const HardwareIndexBufferSharedPtr& indexBuffer) = 0;

    };

    enum ShadowRenderableFlags
    {
        SRF_INCLUDE_LIGHT_CAP = 0x00000001,
        SRF_INCLUDE_DARK_CAP  = 0x00000002,
        SRF_EXTRUDE_TO_INFINITY  = 0x00000004
    };

    class _OgreExport ShadowCaster
    {
    public:
        virtual ~ShadowCaster() { }
        virtual bool getCastShadows(void) const = 0;

        virtual EdgeData* getEdgeList(void) = 0;
        virtual bool hasEdgeList(void) = 0;

        virtual const AxisAlignedBox& getWorldBoundingBox(bool derive = false) const = 0;
        virtual const AxisAlignedBox& getLightCapBounds(void) const = 0;
        virtual const AxisAlignedBox& getDarkCapBounds(const Light& light, Real dirLightExtrusionDist) const = 0;

        typedef vector<ShadowRenderable*>::type ShadowRenderableList;
        typedef VectorIterator<ShadowRenderableList> ShadowRenderableListIterator;

        virtual ShadowRenderableListIterator getShadowVolumeRenderableIterator(
            ShadowTechnique shadowTechnique, const Light* light, 
            HardwareIndexBufferSharedPtr* indexBuffer, 
            bool extrudeVertices, Real extrusionDistance, unsigned long flags = 0 ) = 0;

        static void extrudeVertices(const HardwareVertexBufferSharedPtr& vertexBuffer, 
            size_t originalVertexCount, const Vector4& lightPos, Real extrudeDist);
        virtual Real getPointExtrusionDistance(const Light* l) const = 0;
    protected:
        Real getExtrusionDistance(const Vector3& objectPos, const Light* light) const;
        virtual void updateEdgeListLightFacing(EdgeData* edgeData, 
            const Vector4& lightPos);

        virtual void generateShadowVolume(EdgeData* edgeData, 
            const HardwareIndexBufferSharedPtr& indexBuffer, const Light* light,
            ShadowRenderableList& shadowRenderables, unsigned long flags);
        virtual void extrudeBounds(AxisAlignedBox& box, const Vector4& lightPos, 
            Real extrudeDist) const;


    };
}

#endif